A little bit of oil goes a long way
The oil in a car engine must be changed every few months. Because the oil sits in the bottom of the engine called the sump, the oil is referred to as sump oil. The oil starts to collect grit as well as breaking down due to the high temperature in the engine. Clean engine oil will help the engine to last a lot longer. When the car has its engine oil changed and the engine tuned to run better, it is called getting the car serviced.
Cars engines are complicated, so most people take their car to a mechanic who changes the oil and tunes the car.
Car workshops must have this oil picked up by an appropriate waste disposal truck. This sump oil is usually recycled into other products.
Some people service their own cars and trucks. They then have a problem of what to do with the sump oil. This oil is often poured down drains. A small amount of oil will spread over a large area of water. When the oil is poured onto soil, it can still be washed into creeks, rivers and the sea.